Formation and Evolution of the Solid Electrolyte Interphase on Silicon Electrodes from Fluorine-Free Electrolytes.

With the increasing attention to energy storage solutions, a growing emphasis has been placed on environmentally compatible electrolytes tailored for lithium-ion batteries. This study investigates the surface behavior of Si wafers as model systems cycled with a fluorine-free electrolyte based on lithium bis(oxalato)borate (LiBOB), with and without the additive vinylene carbonate (VC). By utilizing operando X-ray reflectivity (XRR) and ex situ X-ray photoelectron spectroscopy (XPS), the intricate processes involved in solid electrolyte interphase (SEI) formation is elucidated, SiO/Si (de)lithiation, and the impact of the VC additive.

Non-flammable liquid electrolytes for safe batteries.

With continual increments in energy density gradually boosting the performance of rechargeable alkali metal ion ( Li, Na, K) batteries, their safe operation is of growing importance and needs to be considered during their development. This is essential, given the high-profile incidents involving battery fires as portrayed by the media. Such hazardous events result from exothermic chemical reactions occurring between the flammable electrolyte and the electrode material under abusive operating conditions.

Strategies for Mitigating Dissolution of Solid Electrolyte Interphases in Sodium-Ion Batteries.

The interfacial reactions in sodium-ion batteries (SIBs) are not well understood yet. The formation of a stable solid electrolyte interphase (SEI) in SIBs is still challenging due to the higher solubility of the SEI components compared to lithium analogues. This study therefore aims to shed light on the dissolution of SEI influenced by the electrolyte chemistry.

Stabilization of Li-Rich Disordered Rocksalt Oxyfluoride Cathodes by Particle Surface Modification.

Promising theoretical capacities and high voltages are offered by Li-rich disordered rocksalt oxyfluoride materials as cathodes in lithium-ion batteries. However, as has been discovered for many other Li-rich materials, the oxyfluorides suffer from extensive surface degradation, leading to severe capacity fading. In the case of LiVOF, we have previously determined this to be a result of detrimental reactions between an unstable surface layer and the organic electrolyte.

Elimination of Fluorination: The Influence of Fluorine-Free Electrolytes on the Performance of LiNiMnCoO/Silicon-Graphite Li-Ion Battery Cells.

In the quest for environmentally friendly and safe batteries, moving from fluorinated electrolytes that are toxic and release corrosive compounds, such as HF, is a necessary step. Here, the effects of electrolyte fluorination are investigated for full cells combining silicon-graphite composite electrodes with LiNiMnCoO (NMC111) cathodes, a viable cell chemistry for a range of potential battery applications, by means of electrochemical testing and postmortem surface analysis. A fluorine-free electrolyte based on lithium bis(oxalato)borate (LiBOB) and vinylene carbonate (VC) is able to provide higher discharge capacity (147 mAh g ) and longer cycle life at C/10 (84.

Surface Engineering Strategy Using Urea To Improve the Rate Performance of Na Ti O in Na-Ion Batteries.

Na Ti O (NTO) is considered a promising anode material for Na-ion batteries due to its layered structure with an open framework and low and safe average operating voltage of 0.3 V vs. Na /Na.

Effect of the Particle-Size Distribution on the Electrochemical Performance of a Red Phosphorus-Carbon Composite Anode for Sodium-Ion Batteries.

Red phosphorus (RP) is a promising candidate as an anode for sodium-ion batteries because of its low potential and high specific capacity. It has two main disadvantages. First, it experiences 490% volumetric expansion during sodiation, which leads to particle pulverization and substantial reduction of the cycle life.

Interfacial Reaction Mechanisms on Graphite Anodes for K-Ion Batteries.

Potassium-ion (K-ion) batteries (KIBs) potentially offer numerous advantages over conventional lithium-ion batteries as a result of the high natural abundance of potassium and its lower positive charge density compared with lithium. This introduces the possibility of using K-ion in fast charging applications, in which cost effectiveness is also a major factor. Unlike in sodium-ion batteries, graphite can be used as an anode in K-ion cells, for which an extensive supply chain, electrode manufacturing infrastructure, and knowledge already exist.

Unlocking high capacities of graphite anodes for potassium-ion batteries.

Graphite is considered a promising candidate as the anode for potassium-ion batteries (KIBs). Here, we demonstrate a significant improvement in performance through the ball-milling of graphite. Electrochemical techniques show reversible K-intercalation into graphitic layers, with 65% capacity retention after 100 cycles from initial capacities and extended cycling beyond 200 cycles.

Capacity fading mechanism of tin phosphide anodes in sodium-ion batteries.

Tin phosphide (Sn4P3) is here investigated as an anode material in half-cell, symmetrical, and full-cell sodium-ion batteries. Results from the half-cells using two different electrolyte salts of sodium bis(fluorosulfonyl)imide (NaFSI) or sodium hexafluorophosphate (NaPF6) show that NaFSI provides improved capacity retention but results from symmetrical cells disclose no advantage for either salt. The impact of high and low desodiation cut-off potentials is studied and the results show a drastic increase in capacity retention when using the desodiation cut-off potential of 1.

Surfactant-mediated electrodeposition of bismuth telluride films and its effect on microstructural properties.

We report the synthesis of highly crystallographically textured films of stoichiometric bismuth telluride (Bi(2)Te(3)) in the presence of a surfactant, sodium lignosulfonate (SL), that resulted in the improved alignment of films in the (110) plane and offered good control over the morphology and roughness of the electrodeposited films. SL concentrations in the range 60-80 mg dm(-3) at a deposition potential of -0.1 V vs SCE (saturated calomel electrode) were found to yield the most improved crystallinity and similar or superior thermoelectric properties compared with results reported in the literature.